Today's public spectacle is scheduled after a short trip to the President's Moneygall, Co Offaly, ancestral home in the Irish midlands.

Security is expected to be tight today. Access will not be restricted to the free concert and presidential address on College Green but those attending will be screened and gates will open at 2pm.

Mr Obama will speak to the crowd of thousands at the same location where President Bill Clinton wooed onlookers in 1995. It will be attended by the US President's wife Michelle and Irish Taoiseach Enda Kenny.

Among those lined up to play are Sharon Shannon, Mundy, The Coronas, Imelda May and Jedward.

Leading Irish actors will give readings, among them Brendan Gleeson and Gabriel Byrne.

Top sporting figures, such as Padraig Harrington, Robbie Keane and Brian O'Driscoll, will also take part.

Up to 10 venues were examined for the event, including O'Connell Street, the Royal Hospital in Kilmainham, Croke Park and the Phoenix Park, but the others were ruled out for security or traffic reasons.

Mr Obama, who has Irish, Kenyan and American roots, is expected to highlight the strong ties between Ireland and the US.

Large screens will be in place on College Green to enable all present to see those on stage.

The show is scheduled to run for more than two hours.

Unlike the Queen's tour, which concluded on Friday, it is not a state visit and will not carry the same degree of ceremony but recognises the special ties which many Irish people have with America.

Almost 37 million people in the US claim Irish heritage, most dominantly in cities such as Boston, New York and the President's political powerbase in Chicago.

President Obama will be the sixth President to visit Ireland. The first was made by John F Kennedy in 1963. The US is Ireland's largest trading partner and the country's investment has created more than 89,000 jobs.

After landing at Dublin airport in Air Force One, Mr Obama and the first lady will call on Irish President Mary McAleese at her Dublin residence, the Aras an Uachtarain. They will sign the visitors' book and there will be a tree planting ceremony. Two children will ring the Peace Bell and greet the President and his wife.

The meeting with Mr Kenny and his wife Fionnuala will take place at the Irish state guesthouse at Farmleigh House in Phoenix Park.

The Taoiseach and his deputy Eamon Gilmore will meet the president in the dining room at Farmleigh. They will discuss the economic challenges and steps taken towards Ireland's recovery, the Northern Ireland peace process and co-operation between the two countries on food security.

Amid speculation Irish officials were pushing for the country's multi-billion bailout and international trade to top the talks agenda, a government spokeswoman said: ''All of the issues of a national interest will be discussed.''

Mr Obama will be taken by helicopter to Moneygall for a 20-60 minute visit. His great-great-great-great-grandfather was a shoemaker in Moneygall and his son, Falmouth Kearney, left for New York in 1850.

Residents queued for up to six hours on Thursday to secure a ''golden ticket'' to see his homecoming. It will involve a trip down Main Street to the Kearney ancestral home, where he will be greeted by John Donovan, the owner of the house, and his family. The President and First Lady will then visit Ollie Hayes' pub to meet extended family members including representatives of the Healy, Donovan and Benn families.

Obama fever is sweeping the village, with US secret service agents moving in as locals paint their houses and repair the footpaths.

Gales gusting at up to 70mph are forecast in Ireland during the visit.